rccb

Discussion in 'Electrics UK' started by KDOE, 1 Feb 2006.

This topic originated from the How to page called Miniature circuit breakers (MCBs).

  1. KDOE

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    Can anyone tell af a rccb is a sutible substitute for a rcd on a sower radial circuit, the shower is 9.5kw on 10mm cable with a run of about 15 meters, rccb is 45a on cu. thanks
     
  2. Qedelec

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    RCCB is Residual Current Circuit Breaker and is the full name for what most refer to as a RCD or Residual Current Device.
    So the answer is Yes!
     
  3. KDOE

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    Thanks for that,

    Can you or anyone tell me the best way to connect a duel element immersion (seperate side elements), ?
     
  4. JohnD

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    You will need an MCB as well, of course.
     
  5. tomgunn

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    Hi.. I think that you are getting confused between an RCCB and an RCBO, I think that you mean to ask about an RCBO as an RCCB / RCD is for mains switching. If you use an RCD / RCCB then you would use MCB’s for mechanical protection but if you use an RCBO, ( which I believe that you really mean ), then you don’t need an RCD for mains switching!

    If you do use an RCBO then what you have is a fuse devise that combines an RCD & an MCB in one...so theres no need fo an RCD!

    If you’re changing a CCU, ( Customers Consumer Unit ), then you would need to offer the correct protection as per the current IET / 17th edition / regs or if you’re running a new circuit and if you’re extending an existing circuit then your test should be for the disconnection time of the extended circuit of around 0.4sec / 0.2sec etc.. but if you have the old 3036 / re-wireable fuses it is unlikely that you get this osrt of reading!

    For your shower unit on a 45amp fuse / RCBO / MCB etc then the cable size you would require, ( and there are several things you need to check out such as does the cable run under insulation etc etc ), would need to be checked although 10mm seems fine... but do check it out as per VD etc!
     
  6. ericmark

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    ELCB = Earth Leakage Circuit Breaker there are two main types the old voltage type now no longer used.
    GFCI = ground fault circuit interrupter same as ELCB again two main types.
    GFI = ELCB as above
    RCD = residual current device is the same as a RCCB.
    RCCB = residual current circuit breaker is a current ELCB
    ALCI = appliance leakage current interrupter yet another name for RCD.

    As far as I am aware all the above normally break all live conductors (Remember neutral is classed as live).

    RCBO = Residual-current Breaker with Overload these units also have a MCB built in and unlike the RCD often do not open all live conductors although some do and one does have to be careful in selecting correct type.

    The RCD also is sub-divided into different types and the list is long but two main types “Active” and “Passive”. The active will open with loss of supply so fails safe. The passive will stay connected during a volt drop to below the level to which they will work effectively but are used in most consumer units so after a power failure items like a fridge will continue to work.

    There are main specials including auto re-setting and add on units which attach to a circuit breaker which would need a book to cover them all.

    In the home most are 30ma which is considered the current which is unlikely to cause permanent damage. There are also 10ma versions used for items like pond pumps so in event of failure the main 30ma with not trip. There are also 100ma versions which were used with earth rods before the advent of 17th Edition and do not give enough protection against shock to be used with sockets under 20A.

    Most RCD’s will work within 40ms but some (Type S) normally the 100ma type have a delay built in so they will not trip too often in thunder storms etc.

    For a shower you need a 10ma or 30ma version.

    As to duel or single pole that depends on earthing arrangements. Where a supply with earth rods (TT) is used i.e. Caravans, Boats and some houses than normally a duel pole is used or required. But with a PME (TN-C-S) often a single pole is considered as enough.
     
  7. Spark123

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    RCD is a generic term for all of the devices which operate on residual current. An RCCB is an RCD. An RCBO is an RCD. A SRCD is an RCD. GFCI is American. The OP was in 2006 and things have changed since then too.
     

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